The power is 833.3 W
Explanation:
First of all, we need to calculate the work done in lifting the barbell, which is equal to the change in gravitational potential energy of the barbell:

where
mg = 1250 N is the weight of the barbell
h = 2 m is the change in height
Substituting,

Now we can calculate the power, which is equal to the work done per unit time:

where
W = 2500 J is the work done
t = 3 s is the time taken
Substituting,

Learn more about power:
brainly.com/question/7956557
#LearnwithBrainly
Answer:
Density is defined as:
Density = Mass/Volume
Now, density is an intensive property, this means that if you have 10 grams of a given material or 1000 grams of the same material, in both cases you will find the same density.
Then a roll of 50 pennies has the same density that a single penny.
The measures of a single penny are:
Mass = 2.5 g
Thickness = 1.52 mm
Radius = 9.525 mm
The coin is a cylinder, and the volume of a cylinder is:
V = pi*r^2*h
where:
pi = 3.14
r = radius = 9.525mm
h = thikness = 1.52mm
The volume is:
V = 3.14*(9.525mm)^2*1.52mm = 433.015 mm^3
The density will be:
D = 2.5g/433.015mm^3 = 0.00577 g/mm^3
Pretty sure it’s false....................
All matter is composed of atoms, indestructible building blocks.